SOAP interoperability -- "The state of SOAP interoperability is really sad, but a myth that needs some whacking is that web services == SOAP. The myth is that you can't do web services with less than SOAP. A somewhat symmetrical myth is that XML-RPC is enough to do web services. SOAP with WSDL is certainly ideal for Rapid Application Development in Visual Studio .NET and is worth talking to for just that reason, but its too complex to be useful if you want to glue to Unix platforms." (Comments: An article for geeks, but it includes some frustrations I didn't know about. Learn more about SOAP?)